Fluval FX5 Lock Clamp, Assorted Replacement Lock Clamp for the Fluval FX5 Model Easy to replace Fluval FX5 is for aquariums up to 400 gallons The Fluval FX5/FX6 Replacement part may either ship to you as a white piece or as a grey and orange piece. Both pieces work for the Fluval FX5/FX6